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1.
Childs Nerv Syst ; 40(1): 87-97, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37682305

RESUMO

PURPOSE: Posterior fossa tumour surgery in children entails a high risk for severe speech and language impairments, but few studies have investigated the effect of the tumour on language prior to surgery. The current crosslinguistic study addresses this gap. We investigated the prevalence of preoperative word-finding difficulties, examined associations with medical and demographic characteristics, and analysed lexical errors. METHODS: We included 148 children aged 5-17 years with a posterior fossa tumour. Word-finding ability was assessed by means of a picture-naming test, Wordrace, and difficulties in accuracy and speed were identified by cut-off values. A norm-based subanalysis evaluated performance in a Swedish subsample. We compared the demographic and medical characteristics of children with slow, inaccurate, or combined slow and inaccurate word finding to the characteristics of children without word-finding difficulties and conducted a lexical error analysis. RESULTS: Thirty-seven percent (n = 55) presented with slow word finding, 24% (n = 35) with inaccurate word finding, and 16% (n = 23) with both slow and inaccurate word finding. Children with posterior fossa tumours were twice as slow as children in the norming sample. Right-hemisphere and brainstem location posed a higher risk for preoperative word-finding difficulties, relative to left-hemisphere location, and difficulties were more prevalent in boys than in girls. The most frequent errors were lack of response and semantically related sideordinated words. CONCLUSION: Word-finding difficulties are frequent in children with posterior fossa tumours, especially in boys and in children with right-hemisphere and brainstem tumours. Errors resemble those observed in typical development and children with word-finding difficulties.


Assuntos
Neoplasias Encefálicas , Neoplasias Infratentoriais , Criança , Masculino , Feminino , Humanos , Estudos Transversais , Neoplasias Infratentoriais/cirurgia , Neoplasias Infratentoriais/complicações , Idioma , Neoplasias Encefálicas/complicações
2.
Childs Nerv Syst ; 38(4): 747-758, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35157109

RESUMO

PURPOSE: Brain tumours constitute 25% of childhood neoplasms, and half of them are in the posterior fossa. Surgery is a fundamental component of therapy, because gross total resection is associated with a higher progression-free survival. Patients with residual tumour, progression of residual tumour or disease recurrence commonly require secondary surgery. We prospectively investigated the risk of postoperative speech impairment (POSI) and cranial nerve dysfunction (CND) following primary and secondary resection for posterior cranial fossa tumours. METHODS: In the Nordic-European study of the cerebellar mutism syndrome, we prospectively included children undergoing posterior fossa tumour resection or open biopsy in one of the 26 participating European centres. Neurological status was assessed preoperatively, and surgical details were noted post-operatively. Patients were followed up 2 weeks, 2 months and 1 year postoperatively. Here, we analyse the risk of postoperative speech impairment (POSI), defined as either mutism or reduced speech, and cranial nerve dysfunction (CND) following secondary, as compared to primary, surgery. RESULTS: We analysed 426 children undergoing primary and 78 undergoing secondary surgery between 2014 and 2020. The incidence of POSI was significantly lower after secondary (12%) compared with primary (28%, p = 0.0084) surgery. In a multivariate analysis adjusting for tumour histology, the odds ratio for developing POSI after secondary surgery was 0.23, compared with primary surgery (95% confidence interval: 0.08-0.65, p = 0.006). The frequency of postoperative CND did not differ significantly after primary vs. secondary surgery (p = 0.21). CONCLUSION: Children have a lower risk of POSI after secondary than after primary surgery for posterior fossa tumours but remain at significant risk of both POSI and CND. The present findings should be taken in account when weighing risks and benefits of secondary surgery for posterior fossa tumours.


Assuntos
Neoplasias Cerebelares , Neoplasias Infratentoriais , Mutismo , Neoplasias Cerebelares/cirurgia , Criança , Fossa Craniana Posterior/cirurgia , Nervos Cranianos , Humanos , Neoplasias Infratentoriais/complicações , Neoplasias Infratentoriais/cirurgia , Mutismo/epidemiologia , Mutismo/etiologia , Recidiva Local de Neoplasia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Fala
3.
Chemosphere ; 287(Pt 3): 132146, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34537454

RESUMO

Water is used in petroleum oil refineries in significant volumes for cooling, steam generation and processing of raw materials. Effective water management is required at refineries to ensure their efficient and responsible operation with respect to the water environment. However, ascertaining the potential environmental risks associated with discharge of refinery effluents to receiving waters is challenging because of their compositional complexity. Recent European research and regulatory initiatives propose a more holistic approach including biological effect methods to assess complex effluents and surface water quality. The study presented here investigated potential effects of effluent composition, particularly hydrocarbons, on aquatic toxicity and was a component of a larger study assessing contaminant removal during refinery wastewater treatment (Hjort et al 2021). The evaluation of effects utilised a novel combination of mechanistic toxicity modelling based on the exposure composition, measured bioavailable hydrocarbons using biomimetic solid phase microextraction (BE-SPME), and bioassays. The results indicate that in the refinery effluent assessments measured bioavailable hydrocarbons using BE-SPME was correlated with the responses in standard bioassays. It confirms that bioassays are providing relevant data and that BE-SPME measurement, combined with knowledge of other known non-hydrocarbon toxic constituents, provide key tools for toxicity identification. Overall, the results indicate that oil refinery effluents treated in accordance to the EU Industrial Emissions Directive requirements have low to negligible toxicity to aquatic organisms and their receiving environments. Low-cost, animal-free BE-SPME represents a compelling tool for rapid effluent characterization.


Assuntos
Petróleo , Poluentes Químicos da Água , Bioensaio , Disponibilidade Biológica , Indústria de Petróleo e Gás , Petróleo/análise , Petróleo/toxicidade , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
4.
Chemosphere ; 278: 130383, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33845440

RESUMO

Refinery effluents represent an emission source of hydrocarbons (HCs) and other constituents to the environment. Thus, characterisation of effluent quality in terms of concentrations of key parameters relative to permitted standards is important and for total petroleum hydrocarbons (TPH), the specific composition of the HC mixture can affect its toxicity to aquatic organisms. Therefore, this study was designed to analyse TPH, benzene, toluene, ethyl benzene, xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs), (bio) chemical oxygen demand, total nitrogen, total suspended solids and selected metals before, and after, treatment steps to demonstrate removal efficiencies across 13 refineries with variable wastewater treatment systems. Final discharge concentrations of the measured parameters were by 97% within the so called Best Available Technique Associated Emission Levels (BAT-AELs). Further, TPH composition was characterised using high-resolution two-dimensional gas chromatography (GCxGC) analysis to understand the mass distribution by carbon number and specific chemical class. Measurements were compared to SimpleTreat model predictions for validation. SimpleTreat successfully predicted the shape of the effluent composition since it is essentially a removal constant applied to the influent composition. The predictions were of similar magnitude as, or were greater than, the effluent concentrations since SimpleTreat is based on typical performance and is intended to be conservative. This was especially true for aromatic constituents. Reduction in potential HC exposures also coincided with a decrease in predicted toxicity using a mechanistic oil toxicity model, PETROTOX. Overall, the results indicate that EU petroleum refineries are likely to achieve a high performance level regarding effluent treatment.


Assuntos
Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Benzeno , Hidrocarbonetos , Petróleo/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Xilenos
5.
J Hazard Mater ; 388: 122022, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-31962211

RESUMO

Aerobic biodegradation of ethyl tert butyl ether (ETBE) in a gasoline-impacted aquifer was investigated in laboratory microcosms containing groundwater and aquifer material from ETBE-impacted and non-impacted locations amended with either ETBE, or ETBE plus methyl tert butyl ether (MTBE). As sole substrate, ETBE was biodegraded (maximum rate of 0.54 day-1) without a lag in ETBE-impacted microcosms but with a lag of up to 66 days in non-impacted microcosms (maximum rate of 0.38 day-1). As co-substrate, ETBE was biodegraded preferentially (maximum rate of 0.25 and 0.99 day-1 in non-impacted and impacted microcosms, respectively) before MTBE (maximum rate of 0.24 and 0.36 day-1 in non-impacted and impacted microcosms, respectively). Further addition of ETBE and MTBE reduced lags and increased biodegradation rates. ethB gene copy numbers increased significantly (>100 fold) after exposure to ETBE, while overall cell numbers remained constant, suggesting that ethB-containing microorganisms come to dominate the microbial communities. Deep sequencing of 16S rRNA genes identified members of the Comamonadaceae family that increased in relative abundance upon exposure to ETBE. This study demonstrates the potential for ETBE biodegradation within the unsaturated and saturated zone, and that ETBE biodegrading capability is rapidly developed and maintained within the aquifer microbial community over extended timescales.


Assuntos
Etil-Éteres/metabolismo , Água Subterrânea/microbiologia , Microbiota , Poluentes Químicos da Água/metabolismo , Aerobiose , Biodegradação Ambiental , Gasolina , Éteres Metílicos/metabolismo , Microbiota/genética , RNA Ribossômico 16S
6.
J Intern Med ; 285(4): 419-428, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30474313

RESUMO

BACKGROUND: Myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) is receiving increasing interest as a prognostically adverse entity distinct from myocardial infarction with significant coronary artery disease (MI-CAD). However, data are still limited regarding long-term cardiovascular morbidity and cause-specific mortality in MINOCA. METHODS: This is a registry-based cohort study using data from patients admitted to Swedish coronary care units. We investigated various nonfatal outcomes (recurrent MI, hospitalization for heart failure or stroke) and fatal outcomes (cardiovascular, respiratory or cancer-related mortality) in 4069 patients without apparent acute cardiovascular disease, used as non-MI controls, 7266 patients with first-time MINOCA and 69 267 patients with first-time MI-CAD. RESULTS: Almost all event rates (median follow-up 3.8 years) increased in a stepwise fashion across the three cohorts [rates of major adverse events (MAE; composite of all-cause mortality, recurrent MI, hospitalization for heart failure or stroke): n = 268 (6.6%), n = 1563 (21.5%), n = 17 777 (25.7%), respectively]. Compared to non-MI controls, MINOCA patients had an adjusted hazard ratio (HR) of 2.12 (95% confidence interval 1.84-2.43) regarding MAE. MINOCA patients had a substantial risk of cardiovascular mortality and the highest numerical risks of respiratory and cancer-related mortality. Male sex, previous heart failure and chronic obstructive pulmonary disease had a stronger prognostic impact in MINOCA than in MI-CAD. Female MINOCA patients with atrial fibrillation were at particular risk. CONCLUSIONS: Patients with first-time MINOCA have a considerable risk of adverse events. This stresses the need for a comprehensive search of the cause of MINOCA, thorough treatment of underlying disease triggers and close follow-up.


Assuntos
Doença da Artéria Coronariana/mortalidade , Infarto do Miocárdio/mortalidade , Idoso , Causas de Morte , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/epidemiologia , Doença da Artéria Coronariana/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/patologia , Prognóstico , Modelos de Riscos Proporcionais , Recidiva , Sistema de Registros , Suécia/epidemiologia , Resultado do Tratamento
7.
Sci Adv ; 4(10): eaat8131, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30402539

RESUMO

Intracellular delivery of mRNA, DNA, and other large macromolecules into cells plays an essential role in an array of biological research and clinical therapies. However, current methods yield a wide variation in the amount of material delivered, as well as limitations on the cell types and cargoes possible. Here, we demonstrate quantitatively controlled delivery into a range of primary cells and cell lines with a tight dosage distribution using a nanostraw-electroporation system (NES). In NES, cells are cultured onto track-etched membranes with protruding nanostraws that connect to the fluidic environment beneath the membrane. The tight cell-nanostraw interface focuses applied electric fields to the cell membrane, enabling low-voltage and nondamaging local poration of the cell membrane. Concurrently, the field electrophoretically injects biomolecular cargoes through the nanostraws and into the cell at the same location. We show that the amount of material delivered is precisely controlled by the applied voltage, delivery duration, and reagent concentration. NES is highly effective even for primary cell types or different cell densities, is largely cargo agnostic, and can simultaneously deliver specific ratios of different molecules. Using a simple cell culture well format, the NES delivers into >100,000 cells within 20 s with >95% cell viability, enabling facile, dosage-controlled intracellular delivery for a wide variety of biological applications.


Assuntos
Membrana Celular/metabolismo , Sistemas de Liberação de Medicamentos , Proteínas de Fluorescência Verde/administração & dosagem , Nanoestruturas/administração & dosagem , Nanotecnologia/métodos , Proteínas de Neoplasias/administração & dosagem , RNA Mensageiro/administração & dosagem , Molécula 1 de Interação Estromal/administração & dosagem , Eletroporação , Células HEK293 , Humanos , Nanoestruturas/química
8.
Sci Rep ; 7(1): 12790, 2017 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-28986546

RESUMO

As semiconductor electronics keep shrinking, functionality depends on individual atomic scale surface and interface features that may change as voltages are applied. In this work we demonstrate a novel device platform that allows scanning tunneling microscopy (STM) imaging with atomic scale resolution across a device simultaneously with full electrical operation. The platform presents a significant step forward as it allows STM to be performed everywhere on the device surface and high temperature processing in reactive gases of the complete device. We demonstrate the new method through proof of principle measurements on both InAs and GaAs nanowire devices with variable biases up to 4 V. On InAs nanowires we observe a surprising removal of atomic defects and smoothing of the surface morphology under applied bias, in contrast to the expected increase in defects and electromigration-related failure. As we use only standard fabrication and scanning instrumentation our concept is widely applicable and opens up the possibility of fundamental investigations of device surface reliability as well as new electronic functionality based on restructuring during operation.

9.
Bioresour Technol ; 181: 78-89, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25638407

RESUMO

A pilot-scale process was operated over 22 months at the Brussels North Wastewater Treatment Plant (WWTP) in order to evaluate polyhydroxyalkanoate (PHA) production integration with services of municipal wastewater and sludge management. Activated sludge was produced with PHA accumulation potential (PAP) by applying feast-famine selection while treating the readily biodegradable COD from influent wastewater (average removals of 70% COD, 60% CODsol, 24% nitrogen, and 46% phosphorus). The biomass PAP was evaluated to be in excess of 0.4gPHA/gVSS. Batch fermentation of full-scale WWTP sludge at selected temperatures (35, 42 and 55 °C) produced centrate (6-9.4 gCODVFA/L) of consistent VFA composition, with optimal fermentation performance at 42 °C. Centrate was used to accumulate PHA up to 0.39 gPHA/gVSS. The centrate nutrients are a challenge to the accumulation process but producing a biomass with 0.5 gPHA/gVSS is considered to be realistically achievable within the typically available carbon flows at municipal waste management facilities.


Assuntos
Cidades , Poli-Hidroxialcanoatos/biossíntese , Esgotos , Águas Residuárias , Purificação da Água/métodos , Técnicas de Cultura Celular por Lotes , Bélgica , Biomassa , Ácidos Graxos Voláteis/análise , Fermentação , Nitrogênio/farmacologia , Fósforo/farmacologia , Projetos Piloto
10.
ACS Appl Mater Interfaces ; 7(10): 5748-55, 2015 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-25710727

RESUMO

While shell growth engineering to the atomic scale is important for tailoring semiconductor nanowires with superior properties, a precise knowledge of the surface structure and morphology at different stages of this type of overgrowth has been lacking. We present a systematic scanning tunneling microscopy (STM) study of homoepitaxial shell growth of twinned superlattices in zinc blende InAs nanowires that transforms {111}A/B-type facets to the nonpolar {110}-type. STM imaging along the nanowires provides information on different stages of the shell growth revealing distinct differences in growth dynamics of the crystal facets and surface structures not found in the bulk. While growth of a new surface layer is initiated simultaneously (at the twin plane interface) on the {111}A and {111}B nanofacets, the step flow growth proceeds much faster on {111}A compared to {111}B leading to significant differences in roughness. Further, we observe that the atomic scale structures on the {111}B facet is different from its bulk counterpart and that shell growth on this facet occurs via steps perpendicular to the ⟨112⟩B-type directions.

11.
Scand J Med Sci Sports ; 25(1): e116-23, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24716465

RESUMO

The myotendinous junction (MTJ) is a specialized structure in the musculotendinous system, where force is transmitted from muscle to tendon. Animal models have shown that the MTJ takes form of tendon finger-like processes merging with muscle tissue. The human MTJ is largely unknown and has never been described in three dimensions (3D). The aim of this study was to describe the ultrastructure of the human MTJ and render 3D reconstructions. Fourteen subjects (age 25 ± 3 years) with isolated injury of the anterior cruciate ligament (ACL), scheduled for reconstruction with a semitendinosus/gracilis graft were included. Semitendinosus and gracilis tendons were stripped as grafts for the ACL reconstruction. The MTJ was isolated from the grafts and prepared for transmission electron microscopy (TEM) and focused ion beam/scanning electron microscopy. It was possible to isolate recognizable MTJ tissue from all 14 patients. TEM images displayed similarities to observations in animals: Sarcolemmal evaginations observed as finger-like processes from the tendon and endomysium surrounding the muscle fibers, with myofilaments extending from the final Z-line of the muscle fiber merging with the tendon tissue. The 3D reconstruction revealed that tendon made ridge-like protrusions, which interdigitiated with groove-like indentations in the muscle cell.


Assuntos
Lesões do Ligamento Cruzado Anterior , Fibras Musculares Esqueléticas/ultraestrutura , Músculo Esquelético/ultraestrutura , Miofibrilas/ultraestrutura , Sarcolema/ultraestrutura , Tendões/ultraestrutura , Adulto , Ligamento Cruzado Anterior/cirurgia , Reconstrução do Ligamento Cruzado Anterior , Citoesqueleto/ultraestrutura , Humanos , Imageamento Tridimensional , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Músculo Esquelético/transplante , Tendões/transplante , Coxa da Perna , Adulto Jovem
12.
Water Sci Technol ; 69(1): 177-84, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24434985

RESUMO

Polyhydroxyalkanoates (PHAs) are biodegradable polyesters with comparable properties to some petroleum-based polyolefins. PHA production can be achieved in open, mixed microbial cultures and thereby coupled to wastewater and solid residual treatment. In this context, waste organic matter is utilised as a carbon source in activated sludge biological treatment for biopolymer synthesis. Within the EU project Routes, the feasibility of PHA production has been evaluated in processes for sludge treatment and volatile fatty acid (VFA) production and municipal wastewater treatment. This PHA production process is being investigated in four units: (i) wastewater treatment with enrichment and production of a functional biomass sustaining PHA storage capacity, (ii) acidogenic fermentation of sludge for VFA production, (iii) PHA accumulation from VFA-rich streams, and (iv) PHA recovery and characterisation. Laboratory- and pilot-scale studies demonstrated the feasibility of municipal wastewater and solid waste treatment alongside production of PHA-rich biomass. The PHA storage capacity of biomass selected under feast-famine with municipal wastewater has been increased up to 34% (g PHA g VSS(-1)) in batch accumulations with acetate during 20 h. VFAs obtained from waste activated sludge fermentation were found to be a suitable feedstock for PHA production.


Assuntos
Poli-Hidroxialcanoatos/metabolismo , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos
13.
Nano Lett ; 13(9): 4492-8, 2013 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-23941328

RESUMO

Using scanning tunneling microscopy and spectroscopy we study the atomic scale geometry and electronic structure of GaAs nanowires exhibiting controlled axial stacking of wurtzite (Wz) and zinc blende (Zb) crystal segments. We find that the nonpolar low-index surfaces {110}, {101[overline]0}, and {112[overline]0} are unreconstructed, unpinned, and without states in the band gap region. Direct comparison between Wz and Zb GaAs reveal a type-II band alignment and a Wz GaAs band gap of 1.52 eV.

14.
Nanotechnology ; 23(12): 125703, 2012 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-22397834

RESUMO

Mirror electron microscopy (MEM) imaging of InAs nanowires is a non-destructive electron microscopy technique where the electrons are reflected via an applied electric field before they reach the specimen surface. However strong caustic features are observed that can be non-intuitive and difficult to relate to nanowire geometry and composition. Utilizing caustic imaging theory we can understand and interpret MEM image contrast, relating caustic image features to the properties and parameters of the nanowire. This is applied to obtain quantitative information, including the nanowire width via a through-focus series of MEM images.

15.
Scand J Med Sci Sports ; 21(6): e372-83, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21535185

RESUMO

Sarcopenia is a well-known phenomenon in elderly individuals and resistance exercise together with sufficient amino acid (AA) availability has proved to be a counteractive implement. However, the source of AA and supplement timing require further investigation. The objective was to compare muscle protein synthesis (MPS) to intakes of whey and caseinate after heavy resistance exercise in healthy elderly individuals, and, furthermore, to compare the timing effect of caseinate intake. Twenty-four elderly men and women (mean ± SEM; 68 ± 1 years) were randomized to one of four groups: caseinate intake before exercise (CasPre), caseinate intake immediately after exercise (CasPost), whey intake immediately after exercise (Whey), or intake of a non-caloric control drink (Control). Muscle myofibrillar and collagen fractional synthesis rates (FSR) were measured by a primed continuous infusion of L-[1-(13) C]leucine using labeled proteins during a 6-h recovery period. No differences were observed in muscle myofibrillar and collagen FSR with Whey (0.09 ± 0.01%/h) compared with CasPost (0.09 ± 0.003%/h), and it did not differ between CasPre (0.10 ± 0.01%/h) and CasPost. MPS does not differ with whey and caseinate feeding immediately after heavy resistance exercise in elderly individuals, and MPS is similar with caseinate ingestion before and after exercise.


Assuntos
Caseínas/metabolismo , Proteínas Alimentares/metabolismo , Proteínas do Leite/metabolismo , Proteínas Musculares/biossíntese , Treinamento Resistido , Idoso , Idoso de 80 Anos ou mais , Caseínas/administração & dosagem , Colágeno/metabolismo , Proteínas Alimentares/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Leite/administração & dosagem , Desenvolvimento Muscular/fisiologia , Proteínas do Soro do Leite
16.
Vet J ; 173(3): 585-93, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-16647871

RESUMO

Viral infection dynamics and bovine respiratory disease (BRD) treatment rates were studied over six years at a Swedish bull testing station with an 'all in, all out' management system. In August of each of the years 1998-2003, between 149 and 185 4-8-month-old calves arrived at the station from 99 to 124 different beef-breeding herds, and remained until March the following year. Only calves that tested free from bovine viral diarrhoea virus (BVDV) were allowed to enter the station and original animal groups were kept isolated from new cattle in their original herds for three weeks before admission. Although neither prophylactic antibiotics, nor BRD vaccines were used, less than 0.7-13.2% (mean 5%) of the calves (n=970) required treatment for BRD during the first five weeks following entry. This was probably due, at least in part, to the season (the summer months) when the animals were commingled. In the six-month period August-February, 38% of the animals were treated one or more times for BRD and mortality was 0.7%. Hereford and Aberdeen Angus calves had significantly higher treatment rates than Charolais, Simmental and Blonde d'Aquitaine. Serological testing on samples obtained in August, November and January indicated that bovine parainfluenza virus 3 (PIV-3) infections occurred each year before November after entry. Bovine coronavirus (BCoV) infections also occurred every year, but in 3/6 years this was not until after November. Bovine respiratory syncytial virus (BRSV) infections occurred only every second year and were associated with a treatment peak and one death on one occasion (December). The herd remained BVDV free during the entire study period. The infection patterns for PIV-3 and BCoV indicated a high level of infectivity amongst bovine calves, whereas the incidence for BRSV was observed at a lower level. Although the rearing of the animals differed from conventional beef production, the study has shown that commingling animals from many sources is not necessarily associated with high morbidity within the first few weeks after arrival. By preventing BRD soon after commingling the prerequisites for protective vaccination at entry might be improved. Applied management routines are discussed.


Assuntos
Anticorpos Antivirais/sangue , Doenças dos Bovinos/epidemiologia , Infecções Respiratórias/veterinária , Viroses/veterinária , Animais , Cruzamento , Bovinos , Doenças dos Bovinos/prevenção & controle , Doenças dos Bovinos/transmissão , Masculino , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/prevenção & controle , Infecções Respiratórias/transmissão , Estações do Ano , Estudos Soroepidemiológicos , Suécia/epidemiologia , Viroses/epidemiologia , Viroses/transmissão
17.
Phys Rev Lett ; 87(22): 228101, 2001 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-11736428

RESUMO

The charge migration process in DNA is subject to a lively debate among researchers at the moment. We have performed calculations on poly(G)-poly(C) DNA which substantiate a recent report indicating bandlike conduction for this particular form of DNA. Our results show that both guanine and cytosine give rise to conducting channels along the DNA strands. The conductivity results from the overlap of the pi orbitals along the base stacks. We also demonstrate that the measured increase of the threshold voltage with temperature in poly(G)-poly(C) DNA is the result of electron localization due to the structural disorder following high temperature.


Assuntos
DNA/química , Condutividade Elétrica , Modelos Moleculares , Conformação de Ácido Nucleico
18.
Appl Environ Microbiol ; 62(5): 1514-8, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8633850

RESUMO

Aureobasidium pullulans, a cosmopolitan yeast-like fungus, colonizes leaf surfaces and has potential as a biocontrol agent of pathogens. To assess the feasibility of rRNA as a target for A. pullulans-specific oligonucleotide probes, we compared the nucleotide sequences of the small-subunit rRNA (18S) genes of 12 geographically diverse A. pullulans strains. Extreme sequence conservation was observed. The consensus A. pullulans sequence was compared with other fungal sequences to identify potential probes. A 21-mer probe which hybridized to the 12 A. pullulans strains but not to 98 other fungi, including 82 isolates from the phylloplane, was identified. A 17-mer highly specific for Cladosporium herbarum was also identified. These probes have potential in monitoring and quantifying fungi in leaf surface and other microbial communities.


Assuntos
Fungos Mitospóricos/genética , Oligonucleotídeos/isolamento & purificação , RNA Fúngico/genética , RNA Ribossômico 18S/genética , Sequência de Bases , Técnicas de Sonda Molecular , Dados de Sequência Molecular , Oligonucleotídeos/genética
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